Tag - air purifier technology

The Science of Air Purifiers and Health: Is There Data?

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What is one of the hottest gifts in China? Perhaps you could give “the gift that keeps on giving”: an indoor air purifier. They certainly are all the rage in China since last year, with skyrocketing sales and sold-out inventories after the trio of highly publicized airpocalyptic crises. I think this is a good turn of events: plenty of independent testing,including mine, has documented that a good air purifier can dramatically improve your indoor PM2.5 by 80% or more. But is there any good data that proves that this actually makes you healthier? It seems logical, of course, that decreasing exposure to pollution would decrease harmful health effects. But medical history is filled with tales of common sense and tradition that later turn out to be worthless or harmful — like bloodletting, or the more modern tradition of multivitamins. A big percentage of people reading this article take a daily multivitamin, assuming it’s “healthier” to do so, but the best evidence shows they are worthless, and possibly harmful. Could air purifiers be the same?

In theory and in testing, a good purifier should improve a room’s pollution levels more than 80%; this80% reduction is also what the private Association of Home Appliance Manufacturers (AHAM) uses in their clean air delivery rate (CADR) tests, which are widely cited in comparison charts of air purifiers. So let’s say you’ve installed a top-of-the-line purifier in your living room, feeling quite safe and cozy. But how much of your time is actually in that filtered room? Or maybe the purifier is too small for that room size, or the filters are old, or the fan speed is too low, or the windows are open? Even this commonly cited CADR test is just a lab test for only 20 minutes — what about in the real world? I want to take this conversation to the next level, seeking out proof that your health will improve when using these machines. I want to be able to tell my patients and readers that there are published research studies which followed people over many months or even years, compared them to a control group not using air purifiers, and measured their health to see if there was any improvement in heart and lung disease, cancers and death rates. Are there any such studies?258035c025c59745eaab068434d9d6c6

searched the Pubmed scientific database to find the best studies, and I was disappointed but not surprised to find very little strong data. A properly designed research project like this would be very difficult and expensive. But there are a few attempts, especially studies looking at using HEPA filters to help children with asthma. One was a systematic review published in 2002, which found that air filters helped to improve asthma symptoms — but the effect was small, and there was wide variation between studies which made conclusive assessments difficult. A more recent, very well designed study published in Pediatrics in 2011 followed two hundred children with asthma who also were exposed to secondhand smoke at home, and gave half of the kids a true HEPA purifier and the other half a fake purifier for their bedrooms. After a year, the HEPA group of children had less doctor visits for asthma flares, which possibly — but not conclusively — could be due to the 25% decrease in PM2.5 in their homes.

Other studies have focused on allergies, including an interesting study from 2008 which assessed children with documented pet allergies, following them over a year and recording lung function and blood markers. After a year, those who used HEPA air purifiers showed no clear difference in lung function, use of allergy medicines, or blood markers of allergies. Another study back in 1990 was a bit more impressive, showing not only a 70% reduction in indoor PM0.3 but also improved patient symptoms of allergies.

All of these hint at health benefits, but they still dance around the edges of what I want to know for us in China and the developing world. In the USA, most of the air purifier marketing and testing focuses on allergies and asthma. But here in the developing countries, the air pollution is much more severe and thus the health risks are far more serious. We are worried about pollution’s long-term risks of death, heart and lung disease and cancer. These studies I just mentioned still aren’t answering that deeper question: can long-term use of indoor air purifiers prevent death, heart and lung disease, and cancer?

The best study I found was published in January 2013 in Indoor Air. It was very well designed for this complicated type of study, being a randomized double-blind crossover study of 20 homes over three weeks, using an air purifier or a placebo purifier. Their main goal in this remote First Nations community in Canada was to assess whether air purifiers could improve cardiorespiratory health. As their abstract says,

“…each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week… On average, air filter use was associated with a 217-ml increase in forced expiratory volume in 1 second, a 7.9-mm Hg decrease in systolic blood pressure, and a 4.5-mm Hg decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities.”

This same Canadian research team had earlierpublished a similar study, testing 45 non-smokers for 7 days in 20 homes that used wood stoves, comparing health effects with or without HEPA purifiers. The people using the filters showed improved endothelial function and biomarkers of inflammation such as CRP. As most pollution researchers now see pollution as a pro-inflammatory disease, testing for such biomarkers could indeed be an accurate surrogate for later health problems. This approach is also being used in studies of air pollution masks, which I recently reviewed.

My take from these studies? Firstly, they all confirm what we already know: air purifiers can reduce the levels of indoor PM2.5, but with a wide range of effectiveness. Secondly are the more important results looking at health markers. I think the most encouraging finding was the First Nation study showing improvement in lung function, even in such a short amount of time (less than a month). Their data was a bit less convincing on blood pressure improvements, but perhaps a larger study would help confirm their initial findings of a slight improvement.

None of these studies are slam-dunk proof for me, but I honestly don’t know whether we ever will get many more well designed studies like these, unless governmental researchers or Gates-type philanthropists fund them. But until better studies come along, we must rely on what we do know:

  • Air pollution contains many chemicals, but PM2.5 is considered to be the most harmful to health.
  • There is no such thing as a “safe” level of PM2.5. Lower is always better.
  • Worsening PM2.5 causes deaths from all causes, especially heart and lung diseases and cancers. Many studies have shown this, including this 2013 meta-analysis of the population in China.
  • On the brighter side, long-term improvements in PM2.5 do help to decrease mortality. The best study was a huge epidemiological analysis of entire populations in American cities as the air improved from the 1970’s to 1990’s. Lifespans improved for everyone, for a multitude of reasons, and they estimate that 15% of the improved life expectancy was due to cleaner air.
  • Shorter studies have also shown improvements in health from better outdoor air pollution. The best designed study I’ve seen on this happened right here in Beijing, during the 2008 Olympics. A team of researchers followed 125 healthy young doctors before, during and after the Olympics, and found improved blood pressure, heart rate and other biomarkers of inflammation during those lovely days of improved air pollution. Another encouraging studyfollowed pregnant women and their babies in Tongliang, China both before and after a heavily polluting coal-fired power plant was forced to shut down in 2004, and found improved neurodevelopmental scores in newborns at age 2 years.

Is all of this enough to convince you to use an indoor purifier? For me, I was already convinced years ago — it’s not just common sense, it actually makes biochemical sense and also perfectly fits withthe precautionary principle: “When an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.”

Outdoor Air Purifier Makes Your Wait for the Bus 40% Less Smoggy

China’s campaign to wipe out air pollution reduced the levels of dangerous particulate matter in the air by 11 percent last year, according to the Ministry of Environment. But the country still has a long way to go before the air its citizens breathe every day can be considered healthy. Only eight out of the 74 cities surveyed met basic national air quality standards.

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In the meantime, public awareness is rising. Pollution masks are hot commodities and startups making new models for indoor air purifiers are driving prices down. Now, a new invention currently being tested in Hong Kong claims it can reduce air pollution in an open outdoor space by an average of 40 percent (h/t to Techweb).

Under the prototype of the patent-pending system, air is drawn into the system from the inlet located at bottom. The air current then passes through a bag filter, which is effective in removing fine suspended particles (PM10 and PM2.5), before coming out through the Louvre overhead.

Hong Kong has been testing 2 meter-by-3 meter purification station on one of its busiest streets, queen’s Road East in Causeway Bay, since March. Sino Green tells Tech in Asia one unit costs HKD 600,000 (US$77,400 million). (Update: an earlier version of this story referenced the Techweb article that said the project cost US$10 million to develop. Sino Green has informed us that figure is not accurate.)

Air quality at the station can be monitored remotely. Further planned enhancements include smart controllers to manage operating hours more efficiently, solar panels for energy, and a mist cooling system for summer months.

Techweb says the City Air Purification System will be tested at Beijing’s Tsinghua University next. If all goes as expected, it could expand to other mainland cities in the future.

What to Look for When Shopping for an Air Purifier

A lot of people worry about the air they breathe. With all of the cars on the road and factories spewing out toxins, air pollution is pretty bad. What a lot of people don’t realize is that indoor air pollution can be even worse than the pollution outside.

Indoors we have to deal with things like dust, pet dander, mold spores, pollen, volatile organic compounds, fumes from cleaning products and other household chemicals, the list goes on and on. Some of the things floating around in the air inside your home can trigger allergic reactions, and some things can actually make you very sick.

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Because indoor air pollution is such a big problem, buying a good air purifier would be a wise investment and on this page we’re going to tell you what you should look for when shopping for an air purifier.

The world’s largest air purifier is turning Beijing’s dirty air into diamonds

As smog season starts to hit China, Studio Roosegaarde, a design team led by award-winning Dutch designer Daan Roosegaarde, unveiled their pollution-fighting Smog Free Tower in Beijing last Thursday.

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According to the press release, at 7 meters in height, the Smog Free Tower is the largest air purifier in the world — and it’s mobile! Meaning that it can help to clean up other cities if it ever runs out of smog to eat in Beijing.Reuters reports that the tower sucks in 75% of the particles in the nearby air that are dangerous to humans, and then spits back out clean air into the surrounding space.

According to the press release, at 7 meters in height, the Smog Free Tower is the largest air purifier in the world — and it’s mobile! Meaning that it can help to clean up other cities if it ever runs out of smog to eat in Beijing.Reuters reports that the tower sucks in 75% of the particles in the nearby air that are dangerous to humans, and then spits back out clean air into the surrounding space.

 

 

Debate over whether should schools use air purifiers

With the repeat occurrence of smog in China, many parents call for installation of air purifiers in classrooms. Some parents even offered to pay for the purifiers. However it is refused by school authorities. It has caused hot debate over whether air purifiers should enter schools.

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Experts say air purifiers on the market are mostly designed for homes or offices. It still needs evaluation to know if it is useful in classrooms. Education authorities in Shanghai said they will coordinate with relating departments and work for a feasible plan.

Meanwhile, reports said a test has been held in a school in Beijing. After using the air purifier, the level of PM 2.5 in the classroom decreased, but with dozens of students in the enclosed room, the dense of CO2 has passed the healthy standards.

How to Buy an Air Purifier for your home

We’re glad you asked! After being introduced to air purifier technology you might wonder, “This is great, but what does my home air purifier actually do?” It’s a great question; understanding what air purifiers do is important for picking the right one.

To Put it Simply: Air Purifiers Clean the Air

Air purifiers clean your air by passing it through a filtering process that is targeted at removing one or more types of pollutants—dust, allergens, odors, chemicals, and so on.

Olansi K15B Air Purifier

Olansi K15B Air Purifier

What the best air purifier has

  • HEPA filtration. HEPA filtration is regarded by experts as the most effective type of filtration for removing allergens and small particles from the air. Other filters are designed to mimic this effectiveness, but few achieve the ability to remove particles down to 0.1 microns in size or smaller.
  • High maximum air-exchange rate. Maximum air-exchange rate refers to the amount of air an air cleaner is capable of passing through its system in a minute. Air purifiers with higher maximum air-exchange rates will clean the air faster than those with lower rates.
  • Filter-change alert. Many air purifiers come with a counter to let you know when it’s time to change the filter. Some operate on a daily-countdown basis, while others actually base this information on the state of the filter.
  • Dust sensor or air-quality monitor. A few air purifiers have automatic sensors to detect how polluted the air is, with the ability to adjust the purifier’s cleaning speed accordingly without manual intervention. This, of course, provides users with less precise control over energy consumption and noise levels, but it’s a useful feature if you’ll be using an air purifier in a non-occupied space.
  • Several fan speeds. Most air purifiers have multiple fan speeds, which adjust the speed at which the air is cycled through the unit. There’s a direct correlation between higher fan speeds and more noise, however.
  • Large capacity. If you need an air purifier for a small space, more affordable options are practical. But for larger rooms, you’ll need to purchase a more expensive model capable of handling more square footage.
  • Reasonable cost of ownership. Most air purifiers have long-life filters that must be replaced every three to five years. Some models have more than one filter, while others come with a permanent filter meant to be vacuumed periodically instead of replaced. The more frequently you have to replace the filter, the more it will cost you over time.
  • No or very low ozone. Experts say that ozone is effective in neutralizing odors and chemical gases. They also say that this is a classic case where the cure is worse than the disease as high-levels of ozone can be toxic. If you opt for an electronic air purifier, chose a design that emits low or, better still, no ozone. Skip ozone generators sold as air cleaners altogether.

Know before you go

Do you want a whole-house or room air purifier? Experts say that a room air purifier might not be necessary for most individuals. Some owners say they’ve experienced significant relief from allergy symptoms with the use of a $25 furnace filter that works with an existing household unit.

Do you have severe allergy or asthma symptoms? Owners and experts agree that for individuals suffering from severe allergy or asthma symptoms, the investment in top-of-the-line air purifiers is worth it. But if you suffer from only mild symptoms or simply want to reduce smoke or pet dander in your home, a more affordable model can do the trick.

How much space do you have? Air purifiers can be heavy and bulky, with some requiring a few feet of clearance on all sides. Be sure to measure your available space and allow for all space considerations before you buy.

What room will you use an air purifier in? If you’re planning to use an air purifier in your bedroom, for instance, you’ll want to choose a model with a noise level that you can tolerate while sleeping. In living spaces, choose an air purifier with adjustable speed settings so you can turn it up to a higher setting when you’re not in the room to be disturbed by the noise.

Value expectations: The dollars and cents of it

Air purifiers aren’t cheap to own. Many cost several hundred dollars up front, and most replacement filters are fairly expensive — some cost as much as $100 for the HEPA filter, with additional costs for prefilters and carbon filters. Some air purifiers require more frequent filter replacements, which adds to the cost over time. Owners suggest purchasing multiple filter packs online to save money. For those suffering from severe allergies or asthma, the cost is often worth it, and you may be able to purchase it with FSA funds with the proper documentation from your medical professional. Others should try more affordable options, such as furnace filters, which cost significantly less and can be just as effective for most people. While there aren’t a lot of complaints about malfunctioning air purifiers, many models offer warranties of five years for peace of mind. Also, keep in mind that if you can hunt down and eliminate sources of allergens and odors, you might be able to do without an air purifier altogether.